My biggest complaint about the EV-180 is the maintenance. The foam tower gets coated with skimmate, so periodically you have to reach in there with a paper towel or something to get it off. If you're not careful, big chunks of goop will fall back into the body and back into your system. Aside from that, it does a good job.
I suppose if you didn't clean it, it would probably perform just fine. You just wouldn't be able to see what it was doing from the goop coating the foam tower.